Means for venting core boxes



Aug. 9, 1938. 'H. 1.. DEMMLER 7 2,126,997

MEANS FOR VENTING CORE BOXES Filed April 29, 1937 x2593 142 J2 Z2\ Z0? 523 x 13 25 r V I 1i in 1.3 I 15/16 7.5

t k V\ e2 I A Patented Aug. 9, 1938 ED STATES F F! GE,

2,126,091; 7 MEANS- FOR VENTING GOREBO-XES' Henry L. Demmier,, Kewanee,Ill.-

Application' April 29; 1937i SeriaI Nm 139;646

5.- Claims.

My invention relates to molds or core boxes to be used in connectionwithmold orcore making machines: ofthe' type in which-a mold orcorebox'is clamped-I againsta sand container from which o sand is forced intothe moldorcore box bycompressed air.

An object of my inventionis to provide an improved means for venting thecompressed? air passing intoa mold or core box, and also the atllmosph-eri'e air which i's-present in an empty mold. or core box, and atthe sametime to prevent the escape from the mold or core box of the sandwhich is forced thereinto;

Another object is toprovide venting means for 1W core boxes which isless liable to become clogged by particles of sand than are the ventingmeans now in use;

Another object is to provide ventingmeans forcoreboxes which can be moreeasily cleaned of obstructing particles ofsand than are the ventingmeans now used.

Another object is to provide venting means for coreboxes which are moreefficient and have a greater capacity than do the venting means now inuse.

Another object is toprovide an inexpensiveven-ti-ngmeansfor core boxeswhich ismore durable and longer-lived than theventing means now used;

Other objects and advantages'will becomeapparent as the descriptionproceeds;

In the drawing:

Figure I is a. vertical sectional view, somewhat diagrammatic; of a corebox embodying my invention, in position in a core making machine;

Figure 2 is a View of aninside wall of a core box" incorporating oneembodiment of myinvention;

Figure 3 is a section taken onthe line 3-3* of Figure 2;

Figure 4 is a bottom view ofthe structure shown in Figure 3;;

Figure 5' is a sectionaliview, similar to Figure 3, but showing amodified form of my invention; and:

Figure-6 isa sectional view, similar to Figure 3' but showing anothermodified form of my-invention.

Referring to the drawing; I have illustrated in Figure 1 a machinecomprising aframe- I which supports-apressure head 2-. and a sandcontainer 3. It will be understood that the upper end of the sandcontainer is closed, and is provided with pip ing or other suitablemeans. for supplying compressed air or other pressure. thereto. The sandcontainer is further provided with a re-- 55; movable bottom plate- 1:,provided with a. centrat aperture 5 through which the Saudis forced intothe mold; or core box 6.

This mold or core box 6 isshown assupported on bars 1" resting uponthepressure head.- 2*, which is in the form of'a cylinder slidably mountedon a stationary piston 8. The piston 8- has a vertical bore 9"communicating with a pipe I'D connectedwitha source of compressedairorother'pressure fluid; wherebyfluid under pressure maybe admitted'to. the space between the piston 8 and=cyl*- inder 2 to force themoldor; core boxit firmly against the bottom plate 4' of the'sand'containers;

It will be understood-thatthemold or core box-B maybe of any desiredsize or'shape, and thatthe number, and arrangement of the ventingmeanswilldepend upon the size and shape of the mold or core box. Theparticularmold orcore boxshown may be. considered as illustrative only,and is pro,- vided with a laterally extending projection H provided withmy improved venting means, ind-1*- cated generallyat l-2;.Similarventingmeans-t2: are. also-indicated as being provided in thebottom of the box. These venting means i2 may be of any; of the threetypes disclosed in this applica; tion.

The particular type of venting means shown in Figures 2;, 3' and 4comprises a tapered outer sleeve it which has a drive or press fit with.a-wallof the mold or core box 6, it being understood that the term wallis used generically to cover aside, bottom or top part of'the box, oranyprojection orextension thereof-L This sleeve I3 has a. gen-J erallycup-shaped recess M formed in its innerend, and this cup-shaped recesscommunicateswith a plurality of bores l5- arranged in the form of acircle about an enlarged central bore l6 which-may be threaded asindicated at I 1;

As best shown in Figure 3, the central bore l6 and most of thecup-shaped recess I4 are filled by a central member I8 having a threadedstem I-EI which coacts with the threads H of the sleeve l3. to securethemember and sleeve together; The member l8 has'a tapered upperendterminating: in an edge 2.! which cooperates with the'adjacent edge 22of the sleeve F3 to provide a metered annular slot 23 of such size thatair can pass therethrough but sand cannot.

The inner surface 24 of the member I 8 is flat; and lies in the sameplane as the inner end 25: of the sleeve l3 and the inner surface 26 0-1the 50.- adjacent wait of the mold or co-re'box d. It will beunderstood: that where a finegrade of sand isused, the annular slotv 23must be quite small to prevent: the passage of sand. therethroug-h,whereas when a. coarser quality of sanct is: used, a u.

75,, capacity in a small cavity or corner formed in the.

wider slot may be used without permitting the sand to pass therethrough.I therefore make my venting means adaptable to different qualities ofsand by making the member [8 removable and replaceable by a differentmember having a larger or smaller inner end, so that by providing aplurality of members I8 of different sizes, the mold or core box may bereadily adapted for use with different sands. Where the member I8 isscrewed into thesleeve I3 as shown in Figure 3, the inner end of themember I8 is preferably provided with a kerf 21 for receiving the end ofa screw driver to be used in unscrewing the member I8 from its sleeveI3. This removal and replacement can be accomplished without removingvthe sleeve I3 from the mold or core box.

It is important that no projections or depressions be provided on theinner surface of the mold or core box, but that this box have a smoothinner surface exposed to the sand. I therefore find it desirable to fillthe kerf 21 with rubber or other suitable material 28 which can easilybe removed from the kerf 21 by means of a sharp tool when it is desiredto unscrew the member I 8.

I The sleeve I3 and member I8 have their inner ends exposed to the blastof sand entering the mold or core box through the orifice 5, and arethereby subject to a grinding or abrasive action. I therefore prefer tomake the sleeve I3 and the member I8 of steel or other suitable wearresisting material, and I prefer to harden the inner ends of the sleevel3 and member I8 to increase their wear resisting properties. In someinstances it is advisable to harden the entire sleeve and the entiremember rather than their inner ends only.

While the width of the annular slot 23 is less than the diameter of thegrains of sand used in the mold or core box, the annular slot in itsentirety provides a relatively large opening through which the air mayfreely escape from the interior of the mold or core box. The air passingthrough the slot 23 passes between the upper end of the sleeve I3 andthe enlarged head of the member I8, and thence through the bores I toatmosphere. It will be noted that the taper of the enlarged end of themember I8 provides forthe free escape of any particles of sand which maypass through the slot 23, and thereby reduces the likelihood ofclogging.

I have found that a slot of a given width and a length several times itswidth is much less likely to clog than is a circular orifice havinga'diameter equal to the width of the slot. Such a slot is therefore farsuperior to a plurality of such circular orifices, having the sametheoretical venting capacity. Furthermore, it is much easier to removeany particles of sand which may become wedged in such a slot than it isto remove particles of sand becoming wedged in such circular orifices.

I The embodiment shown in Figure 5 is identical with that shown inFigures 2, 3, and 4, except that in the embodiment of Figure 5 themember l8A and outer sleeve I3A have a press fit instead of beingscrewed together as in Figures 2, 3, and 4.

Where the member is press-fitted into its sleeve, it is unnecessary toprovide the member with a kerf such as the kerf 2'! of the embodiment ofFigure 3.

In the embodiment of Figure 6, greater venting capacity is provided in asmall area, and this form of my invention is particularly desirableWhere it is essential to provide the maximum venting wall of the mold orcore box. In this form of my invention I provide an outer sleeve 30which is press-fitted into the wall of the mold or core box, as in theprevious embodiments. The inner end of this sleeve 30 is provided with alarge cupshaped recess 3| which communicates with a plurality of bores32 arranged in the form of a circle about a large central bore 33.

An inner sleeve 34 is threadedly or otherwise secured in the bore 33 andhas an enlarged inner end 35 providing an edge 36 cooperating with theadjacent edge 37 on the outer sleeve to form an annular slot 38, throughwhich the air may escape but which is too small to permit the passage ofsand therethrough. The inner end of the inner sleeve 34 is likewiseprovided with a cup-shaped recess 39 communicating with a plurality ofbores 4Il arrangedin the form of a circle about a central bore 4 I. Amember 42 is threadedly or otherwise secured in the bore 4| and has anenlarged inner end 43 providing an edge 44 which cooperates with theadjacent edge 45 on the inner sleeve to provide a second annular slot 46for the escape of air. This slot likewise is too narrow to permit theescape of sand therethrough.

It will be understood that where the member 42 is threadedly secured inthe inner sleeve 34, this member 42 is provided with a kerf 41 which maybe filled with rubber or other suitable material 43. The inner sleeve 35may also be provided with holes 49 for receiving the prongs of a toolused in unscrewing this inner sleeve from the outer sleeve 35. Theseholes 49 may likewise be filled with rubber or other suitable materialso that a smooth surface is provided for contact with the sand in themold or core box.

It is to be understood that my invention is not limited to theparticular form shown in the drawing, and that the scope of my inventionis to be limited solely by the following claims.

I claim:

7 1. Venting means of the class described, comprising a box, a sleevepress fitted thereinto, said sleeve having a circular recesscommunicating with a central bore and a plurality of bores grouped aboutsaid central bore, a second sleeve located in said central bore andhaving cooperation with an end of said first named sleeve to provide anannular slot for permitting passage of air therethrough but forpreventing passage of sand therethrough, said second sleeve having acircular recess communicating with a central bore and a plurality ofbores grouped about said central bore, and a member located in said lastnamed central bore, said member having an end located in said last namedrecess and cooperating with an end of said second sleeve to provide asecond annular slot adapted to permit passage of air therethrough butadapted to prevent passage of sand therethrough.

2. Venting means of the class described comprising a wall member havingan aperture therein providing an enlarged portion opening upon a side ofsaid wall member along a well defined edge of predetermined dimensionsabout a predetermined axis, a second member disposed in said enlargedportion. having an end face and a tapering circumferential facecentrally located with respect to said enlarged portion, said taperingface intersecting said end face along a second well defined edge havingdimensions corresponding with and slightly less than said firstdimensions to provide a clearance between said edges to permit thepassage of air therethrough exclusive of core sand, means for securingsaid members axially 7 relative to each other, and means for connectingsaid enlarged portion to atmosphere.

3. Vent means of the class described comprising a wall having anaperture therein defining a surface of revolution and providing anenlarged portion opening upon the inside of said wall along a welldefined marginal edge and an internally threaded reduced portion openinginto said enlarged portion, means for venting said enlarged portion tothe atmosphere independently of said reduced portion, and a headedmember having a marginally well defined end face threadedly received insaid reduced portion to a depth whereby said end face is approximatelyflush with said wall and the marginal edge of said end face is closelyproximate to the marginal edge of said enlarged portion to permit thepassage of air therebetween exclusive of core sand, the headed portionadjacent said enlarged portion having a circumferential face defining asecond surface of revolution inclined to said first surface ofrevolution whereby the clearance between. said headed member and saidenlarged portion is relieved behind said marginal edges.

4. Venting means of the class described comprising a wall member havinga compartment on a side thereof bounded by a well defined edge of apredetermined contour, a second member disposed in said compartmenthaving a tapering face of a cross-sectional contour similar to saidfirst contour, said contours being slightly different as regards theircorresponding dimensions to provide a clearance permitting passage ofair between said members exclusive of core sand granules of apredetermined size, means for moving one member relative to the other tovary the amount to said clearance, and means for venting saidcompartment to atmosphere.

5. Venting means of the class described comprising a sleeve, a secondsleeve disposed in said first sleeve with sufiicient clearancetherebetween to provide a restricted slot permitting passage of airtherethrough to the exclusion of core sand, and a member disposed insaid second sleeve with clearance between said member and said secondsleeve to provide a second restricted slot permitting passage of airtherethrough to the exclusion of core sand, means for detachablysecuring said sleeves together and said members to said second member,and means for venting said slot to the atmosphere.

HENRY L. DEMMLER.

